2008 Off road, Lipo

[mark christopher]

will it happen for regionals and nationals?

wada u all tink?

[paulc]

i hope it does happen :)

[Lew]

Would be nice.

[losixxx]

can't see it myself

[PaulRotheram]

cant see it happening either.. too many cars that cant use them.

[TRF_Tastic]

Nope me neither.

[DCM]

got to get construction rules first, then a lot of cells will be illegal...

They go bang you know (had to put that it.... roflol)

[Chris Doughty]

did you all hear about the exibition class at the US Mod nationals?

LiPo class for their trucks, 20 minute finals, most of the factory drivers raced it, I quite like the idea of long finals... ?

[mark christopher]

cant see it happening either.. too many cars that cant use them.
saddle packs will be available, the only cars are the ones with a non stick/sadle layout, nimh would still be legal or cars change to suit.

no tc is is designed to run 5 cells but they are!!

[DCM]

if it were to happen, then there would need to be new scrutineering processes in place and strict weight regulation.

[dan_kitty]

lipo would make my life so much easier at regonals where i race 2 clsses on the same day.

[mark christopher]

if it were to happen, then there would need to be new scrutineering processes in place and strict weight regulation.
so what would change from now? dont cars get checked? what would need to change?

[burgie]

There are not that many cars that can't use them - probably only the X-Factory cars and the Atomic Carbon Car.

You can get Li-Po saddle pack cells, and they fit inside an X10, so if they fit in that they will fit in the other cars that run saddle packs.

As for the x-factory and atomic carbon cars, I would guess that those manufacturers are either working on a chassis that will accept Li-Po packs easily or will be able to engineer a solution. Because the Li-Po's are so much lighter than Ni-Mih I think that the weight distribution issue could be addressed with the minimum of fuss.

If the customer demands cars that will run li-po, and i am sure they will in a very short space of time, if they become "legal" then the car manufacturers will listen and they will release chassis/conversions to accept li-po. Either that or loose business.

Personally, I would love to see Li-Po's made legal in off-road. I love 'em! ;)

[OldTimer]

Max amps can produce Lipo's that fit the S4 ;)

[dan_kitty]

the x6 can take lipo i believe

[Sabben]

did you all hear about the exibition class at the US Mod nationals?

LiPo class for their trucks, 20 minute finals, most of the factory drivers raced it, I quite like the idea of long finals... ?

The motor and esc will get very hot if you're driving in 20min. I notice that my brushless system gets quite hot after a heat/ 5 min. Or am I wrong?

[burgie]

Max amps can produce Lipo's that fit the S4 ;)

Dude! That's one car that's back into the Li-Po equation then!

the x6 can take lipo i believe

I know the X6 can, but not in the way that the chassis was designed - the X6 takes the cells in a "conventional" way straight across the middle, with plenty of room for weight in the "2-cell" position, but the chassis was designed to take the cells primarily in a 4+2 configuration for better weight distribution with the mid motor setup, as i understand it.

[dan_kitty]

true, so i guess irt would be a comprimise then,

[burgie]

I don't see why you couldn't do that - you need to make up around 200g if you run the team orion "carbon" cells, so you may as well put the weight where it is central, i suppose.

[mark christopher]

true, so i guess irt would be a comprimise then,
yes lipo accross car balast to bring up to weight in the slot where the two cells would have been

[Chrislong]

The X-6 was designed for 4+2 cells and for stick LIPO pack accross the chassis, the battery bar turns over and is shaped specifically for the LIPO cells. The weight of LIPO is less, so there is no issue with the weight being wide - and we can use lead to bring the weight forward if required.

As for the X-5 - it will be easy for us (im talking personally) to adjust the chassis with dremel and re-drill for straps to hold the saddle LIPO packs. Changing the car to a 3+3 config but seeing that LIPO is much lighter, we would add lead to bring the balance back.

I think the issue is with the nominal rated voltage being higher than cells.

I would like LIPO to be accepted and intigrated into the same classes as NIMPH's, but its all down to the manufacturers submitting them, us attending the AGM and voting them in, and the BRCA EB accepting them - for which to do I guess EFRA and ROAR would have to do the same so it is a sweeping change for the class's internationally. :wtf:

[mark christopher]

this is a comment i make all the time to the racers in the scale ic class.
WE are the BRCA and WE can make rules without the rest.
is the eb not an UK body?(qenuine question)
bikes already use them in the brca, without the aproval of the EB, which baffles me some what when everyone else in the tc/buggy world says they have to be EP aporoved etc!

chris id like some nimphs to, where can i get em round our area?;)

[vader]

badger

[modelimages]

got to get over a couple of problems first, first one is voltage 2 cell lipo is 7.4v bit of an advantage over 7.2v from the nimh so you couldn't really run both types of battery together and the next problem is energy we are barely keeping the speedo's and motors together for 5 minutes using 4200 at 7.2v so adding more volts and runtime equals more heat to get rid of.

and the final point is safety, they do go bang and do so in a big way, both in use and whilst being charged 130 drivers at a national = at least one bang!

i can see it coming but not next year

[PaulRotheram]

saddle packs will be available, the only cars are the ones with a non stick/sadle layout, nimh would still be legal or cars change to suit.

no tc is is designed to run 5 cells but they are!!

its not a fact of, will they fit, its will they work?

If i fitted lipos to the back of my bj4, i gurantee you the car would not handle what so ever, the same goes for other cars that rely on the weight over the rear of the cars to give the traction needed such as yokomo, tamiya, losi, hotbodies, aero and many more.
I've seen cars run at my local with lipos, and they look like crap on the track, they compare to the speed of my own car.. with me running brushed equipment also! the only advantage i see is only needing one lipo pack.

Theres a reason why drivers add extra weight in the back of their 2wd cars.. (b4) taking away alot of the weight would make it alot worse from my view.

I'm happy with the way things are, more runs through the day which is great as we only run 5 minutes, if id turn up to a national and be confronted with a format of 3 runs and a final (longer finals) i'd not even bother as it'd not be worth the trip.

Racing is lazy enough as it is due to brushless, cells that dont need much maintinance and spektrum radio equipment has made even little things such as crystal changes redundant..

Why is there a need of a big change for lighter cells, when they perform the same (speed wise), and make the car handle worse (in offroad).

[Cockerill]

I understand what your saying Paul but you cannot seriously expect to half the weight of the heaviest component and expect the car to handle the same without any set-up changes and/or car changes.

In touring cars they have lost a cell (70g) and the cars are going as quick, with less wear and improved handling.

In off-road 5 cells can be as quick if not quicker than 6 cells in 2wd.

By using Lipo we can reduce the minimum weight, reduce wear and tear, possibly even tyre wear.

Isn't light right? ;)

My personal thoughts on Lipo for 2008 are that it won't happen, we currently have no rules for them. We had brushless rules 1 or 2 years before they became mainstream, and yet another year before thy came legal.

[PaulRotheram]

I know they will need setting up different for sure, but ive seen the cars in action, and even tried one or two and they are not right.

I may be in the minority, i may not.. however it's my opinion, but even if lipos are introduced things will still be the same. The people at the top will still be there, they will most likely have more than one pack which is one of the few advantages the lipos give, they will still use 3-4 sets of tyres through a day for the edge..
It just seems alot of effort for very little gain, at least brushless has prooved useful and moving racing forward.

[Chrislong]

this is a comment i make all the time to the racers in the scale ic class.
WE are the BRCA and WE can make rules without the rest.
is the eb not an UK body?(qenuine question)
bikes already use them in the brca, without the aproval of the EB, which baffles me some what when everyone else in the tc/buggy world says they have to be EP aporoved etc!

chris id like some nimphs to, where can i get em round our area?;)

Hi Mark, The EB is the Electronic Board, they accept submissions from companies for approval, write approval lists and test the equipment for abiding by the rules. The EB is part of the BRCA, I am sure there is some info on the BRCA website about why it was formed - but in a nutshell, the EB writes one list which then covers 1/12, 1/10 OR, 1/10 TC, etc, and so each class don't need to go writting independent lists... The EB is basically one man, probably the only man worthy of such a task too - Paul Worsley.

Contact details on BRCA website for him, he is good at clearing up any questions regarding technicallities of things, and will get a far more certain answer than us lot on the forum ;)

NIMPHS :D They're all over the place Mark, just go over and ask... :D

Paul - although what you say is true, those cars were ones racing on NIMPHS and then put LIPO in for a play (Barry Weldon? Chris Evison?), therefore the car unchanged. If we were to switch to LIPO fulltime, then we'd be using more lead (a good thing), using softer suspension and changing the setup a lot more to suit.

Chris

[PaulRotheram]

nope, neither of them drivers.. however who it is is irrelevent.

I cant see using more lead as being a good thing, as we would be back to where we are now.. maybe not as much but not far off either.

No one has actually shown a worthy benefit of changing to lipo from our current situation (what is actually wrong with the current set up.. anyone???), so far i only see them as being lighter and needing less of them (however still expensive at £75 a pop).

Can some one give me a good reason for the effort to change over to lipo from our current situation?

The outcome dosnt matter for me, i go with the flow, but i'm interested to know why we should change.

[DCM]

The bikes use them as they voted not to use the EB's homologation list for cells.... simple as that, that is what that section voted.

Yes, you are the BRCA, but for a rule change, you must wait till the AGM, propose a change, get it seconded and hope there is a lot of like minded people to help you vote it through. Otherwise, the EB is group of people voted into certain positions to ensure motors and batteries conform to the given rules that we have voted through.

As for 'ALL CARS' can use Lipo..... yes and no, at the moment, where the weight of a car is set so that it conforms with cell weight too, it means you can ballast out the 'inbalance' that running a LiPo pack induces..... when the class weights drop to a LiPo level, then cars will have to be redesigned to obtain an optimum balance front to rear, left to right.

[mark christopher]

got to get over a couple of problems first, first one is voltage 2 cell lipo is 7.4v bit of an advantage over 7.2v from the nimh so you couldn't really run both types of battery together and the next problem is energy we are barely keeping the speedo's and motors together for 5 minutes using 4200 at 7.2v so adding more volts and runtime equals more heat to get rid of.

and the final point is safety, they do go bang and do so in a big way, both in use and whilst being charged 130 drivers at a national = at least one bang!

i can see it coming but not next year

ok and a higher voltage (all be it .2volt) does what to amps for the same wattage draw?
at biws in 6 cell touring car lipo and nimh ran side by side lipo took one win, (all cars to same weight) the advantage is in no loss of performance and easier charging.

if miss used they do go bang yes, but so does any form of power cell. to date only nimh has cost one racer a very badly injured eye and another not so good, lipo has non documanted. simply dont miss use em (corectly charge and dont go below 6 volts) and there safe, how many carry em in your pocket? (mobile phone)
to say they go bang and plead ignorance to any other cell being a danger is very poor knowledge!

[mark christopher]

Hi Mark, The EB is the Electronic Board, they accept submissions from companies for approval, write approval lists and test the equipment for abiding by the rules. The EB is part of the BRCA, I am sure there is some info on the BRCA website about why it was formed - but in a nutshell, the EB writes one list which then covers 1/12, 1/10 OR, 1/10 TC, etc, and so each class don't need to go writting independent lists... The EB is basically one man, probably the only man worthy of such a task too - Paul Worsley.

Contact details on BRCA website for him, he is good at clearing up any questions regarding technicallities of things, and will get a far more certain answer than us lot on the forum ;)

NIMPHS :D They're all over the place Mark, just go over and ask... :D

Paul - although what you say is true, those cars were ones racing on NIMPHS and then put LIPO in for a play (Barry Weldon? Chris Evison?), therefore the car unchanged. If we were to switch to LIPO fulltime, then we'd be using more lead (a good thing), using softer suspension and changing the setup a lot more to suit.

Chris
i know ;) my point was the bikes dont run to eb rules/regs, so other could

[mark christopher]

nope, neither of them drivers.. however who it is is irrelevent.

I cant see using more lead as being a good thing, as we would be back to where we are now.. maybe not as much but not far off either.

No one has actually shown a worthy benefit of changing to lipo from our current situation (what is actually wrong with the current set up.. anyone???), so far i only see them as being lighter and needing less of them (however still expensive at £75 a pop).

Can some one give me a good reason for the effort to change over to lipo from our current situation?

The outcome dosnt matter for me, i go with the flow, but i'm interested to know why we should change.
Paul apreciate you opinion its why i started this thread.

my views on benifits, lighter, less packs reguired, no drop of in perfomance from 1st to over 100th charge, cool and recharge same day no discharging cycling etc, just top em up. charge em week before and there ready to race, just as safe if used correctly

[burgie]

Paul - although what you say is true, those cars were ones racing on NIMPHS and then put LIPO in for a play (Barry Weldon? Chris Evison?), therefore the car unchanged. If we were to switch to LIPO fulltime, then we'd be using more lead (a good thing), using softer suspension and changing the setup a lot more to suit.

Chris

Hi Chris - the car's Paul is referring to are mine and Craig Magee's.

Now, with no disrespect to craig, but neither of us are the greatest drivers, just average club racers really I suppose. (although craig is better than me! :wtf:)

I haven't altered my car' setup apart from sticking extra weight down the middle (200g's) and backed the slipper off.

If the cars (especially mine) were setup properly to run Li-po's (or nimih for that matter!) then the difference in handling would be minimal I am sure. Infact as the extra weight can be added pretty much just where you want it, then the handling would probably be better. My car is conservatively geared to be quick enough for me - it could be faster, but not with me behind the sticks.

The main advantage Li-Po has over nimih is the constant performance and overall cheapness. £80 will buy two packs of Li-Po's that looked after properly (i.e. balance charged) should last over 2 years, and to me, that's cheap performance - they are a simple way to increase performance. Pauls car may be quick with brushed equipment, but mine is cheaper to keep going fast! No equalizing equipment, no dischargers needed and relatively cheap chargers - t's all good to me.

For all those who say that if it ain't broke don't fix it is a very short sighted view to take. As a hobby we need to embrace change and move forwards with it so that we are not left lagging behind in 5-10 years time. If we had ignored brushless systems three years ago, we wouldn't be reaping the rewards of them now, so let's not ignore Li-Po's now and enjoy the benefits they will bring to the hobby in the future.

[DanW]

Cars would need re-designing to get the handling right.

From what i've seen a 2WD off road car with lipo and brushless has an uncontrolable power to weight ratio.

With a much lighter car you need less torque to get it moving and less power to keep it moving... so less powerful motors would be the key to perfomance. Less power = less wear and tear.

The traditional 2WD buggy design with motor hanging out back would be finished, just not enough weight infront of the rear axle to keep balanced, so would start a big move to mid motor cars.

One advantage of LiPo maybe the environemt? i don't know?

Nicads and Nimhs are fairly nasty things and don't do mother nature any favours - are lipos less nasty?

[PaulRotheram]

My cars are actually quite cheap to keep going.. my motors last a long time between rebrushes being v2 type, my cells are discharged and equalised every month or so depending when i remember, I leave them mid week as the charge is left in them after my previous races.

I was reffering to craigs B4, and mr larkins, both looked uneasy to handle without extra weight.. however with the added weight they looked to be like a regular b4, lipo powered.. but then it's back to where we are now.. with just a change in batterys.

I'm asking is it really worth changing everything for something we will be similar to now, just powered by a different type of cell?
time and effort needs to be considered, and then other people in the world.. if we changed to LIPO, and EFRA didnt.. would our drivers want to change due to the fact they would need to be running the current sub c cells to run at euros and the worlds?

Ease of use and cheap maintinance already exsists, this is why I don't understand what benefits lipo would really give. Some people do discharge and equalise all the time.. but i know pleanty of people who also dont and take the same route as my self and get along fine.
My cells have been having this treatment since november, that's near 8 months and i'm yet to notice a difference in performance.

Where are the two packs of lipos for £80 advertised? I've looked around (briefly i must say) and have found the gold orion one for £75 for one pack, then on top of that i'd need a new charger, and then a second battery as it seems they need to cool down before i can re use them.

With this route i'd in spending close to £250 to get me going.

However as said.. if lipo was introduced i'd follow suit.. but I can't see any benefits as of yet, unlike brushless where no skimming, no brushes and no lathe is really appealing!

[PaulRotheram]

A quick thought.. as im in the trade industry, it seems lipos are becoming more involved with tools such as cordless drills etc, maybe the main manufacturers (outside of racing) who currently produce the sub c cell could have an influjence on our racing if they switch over to lipos full time.

The construction industry is a hell of a bigger scene than RC, and power is always needed.. so maybe lipos is the future in some sence..

[DCM]

I find it hard to believe that the cell matchers, the big ones, wont find a way of increasing performance and character matching of cells, then we are back to where we are.

IB42's have been no problem.

LiPo, once they start getting pushed hard have a similar life span as a normal cell too.

[mark christopher]

I find it hard to believe that the cell matchers, the big ones, wont find a way of increasing performance and character matching of cells, then we are back to where we are.

IB42's have been no problem.

LiPo, once they start getting pushed hard have a similar life span as a normal cell too.
where is that info from?
trakpower have at least one lipo thats been charged over 100 time at ten amps and its still not lost any performance, nimh would have done for definate!

[mark christopher]

My cars are actually quite cheap to keep going.. my motors last a long time between rebrushes being v2 type, my cells are discharged and equalised every month or so depending when i remember, I leave them mid week as the charge is left in them after my previous races.

I was reffering to craigs B4, and mr larkins, both looked uneasy to handle without extra weight.. however with the added weight they looked to be like a regular b4, lipo powered.. but then it's back to where we are now.. with just a change in batterys.

I'm asking is it really worth changing everything for something we will be similar to now, just powered by a different type of cell?
time and effort needs to be considered, and then other people in the world.. if we changed to LIPO, and EFRA didnt.. would our drivers want to change due to the fact they would need to be running the current sub c cells to run at euros and the worlds?

Ease of use and cheap maintinance already exsists, this is why I don't understand what benefits lipo would really give. Some people do discharge and equalise all the time.. but i know pleanty of people who also dont and take the same route as my self and get along fine.
My cells have been having this treatment since november, that's near 8 months and i'm yet to notice a difference in performance.

Where are the two packs of lipos for £80 advertised? I've looked around (briefly i must say) and have found the gold orion one for £75 for one pack, then on top of that i'd need a new charger, and then a second battery as it seems they need to cool down before i can re use them.

With this route i'd in spending close to £250 to get me going.

However as said.. if lipo was introduced i'd follow suit.. but I can't see any benefits as of yet, unlike brushless where no skimming, no brushes and no lathe is really appealing!
a charger can be had for £50 and to be honest there is no difference between my £50 one and my £150 (both do lipo) Jimmys trackpower lipo review shows the charger i have and recomend.

i ran one pack in tc for a full meeting by the time i had marshalled it was cool, they dont get as hot as nimh and you oly have to top them up not charge them from flat, though i would say two is or would be the racers choice.

we seem to add weight to b4's even when there over weight,

my sugestion would be keep the weight lmits as they are now, allow lipo to run along side nimh, as paul has said the top guys will still be at the top, no matter what
to me nimh will still be there, but give racers the choice, even if its a feeder into regionals

[PaulRotheram]

you cant though.. as the current rule is 7.2v.. and lipo isnt.. so its either one or the other unless the barrier is increased so 7.2 is still allowed.. however i can't see this happening my self as of yet.

[Colinevan]

For me, iv just purchased a trakpower 4900, balancer and new charger dedicated for lipo. Iv purchased this lot specifically for use in my Rb5.

The reason being, i decided a few weeks back to run 2wd and 4wd both on club days. It will give me twice the tracktime, however twice the hassle of another car to get ready. For me the selling point was leave the cells in the car, and just stick them back on charge when needed. No swapping cells over, no equalising, less hassle :cool:.

The bonus being, my lipo could be charged weeks in advance and be ready to run without needing re peaking etc. Tbh it was a nightmare trying to run 2 cars as i really had no spare time. If lipo helps its worth the extra outlay in my opinion.

For me personally, less hassle is good, i run brushless for this very reason in both cars, and im now contemplating using a spare sanwa gemin tx rx set just to save swapping the modules over on the Ko and changing the trims etc on model memory. The lipo just compliments the easier maintenance schedule and more time to concentrate on other things.

My aim this year, is to learn to drive more consistently and more importantly to learn how to set a car up (basics only :D;)). Less time with cells more time to learn other things.

Col.;)

[mark christopher]

you cant though.. as the current rule is 7.2v.. and lipo isnt.. so its either one or the other unless the barrier is increased so 7.2 is still allowed.. however i can't see this happening my self as of yet.
not if the rule is changed to " a max nominal voltage of 7.4 volts" that allows both.
if i turn up at a national and run 5 nimh cells to current weight im legal yes? so as i read it i can run up to 7.2, no rules saying i must only run 7.2

[MarkWesterfield]

the big problem with the lighter weight lipo batteries is that you are reducing the amount of weight on the tires which in turn reduces the size of the contact patch of the tire touching the ground. Suspension settings can not change this, only car weight, downforce (only at high speed) or tire/insert compound changes can change the tire contact patch. Going to an even softer compound tire would not be good if the races were made longer to take advantage of the increase of battery capacity. I feel the best solution would be to leave the existing weight rules in place. Racers could add weight to bring the cars to legal weight for the time being. Car manufacturers could then use the weight savings of lipo to design the car parts stronger and more durable, strong enough to last the longer races that lipo can provide. This would really help bring in new racers with the benefit of longer runtimes and stronger cars.

[DCM]

where is that info from?
trakpower have at least one lipo thats been charged over 100 time at ten amps and its still not lost any performance, nimh would have done for definate!

All batteries have a cycle life time, it is the nature of the beast. And the harder you use them, the quicker they degrade. Also, the higher the amp rating the higher the cost, so there we go, right away, you can have budget packs, but they just won't have the build to survive.

[sim]

got to get over a couple of problems first, first one is voltage 2 cell lipo is 7.4v bit of an advantage over 7.2v from the nimh so you couldn't really run both types of battery together and the next problem is energy we are barely keeping the speedo's and motors together for 5 minutes using 4200 at 7.2v so adding more volts and runtime equals more heat to get rid of.

and the final point is safety, they do go bang and do so in a big way, both in use and whilst being charged 130 drivers at a national = at least one bang!

i can see it coming but not next year

First, voltage:
NiMH sub-c cells are still referred to "1.2V" batteries because that's their traditional name. If you read the label on matched IB4200 World Championship cells, you'll find many labelled at 1.3V average (discharged at 30 or often 35 amps). I don't see how a six cell pack made out of these cells can be called a 7.2V pack.

2nd, go bang:
Some LiPos do go bang. It's true. I think ultimately there will be a real need for race organisers to sort out which LiPos are safe and which are not (and its probably safe to guess it will be a long and complicated process, involving cloned products, all sorts of certificates and stickers, danger awareness campaigns, and accusations of bribery, corruption and foul play) so that even accounting for user idiocy, the abused packs will just let out the magic smoke instead of exploding.

[DCM]

no, it isn't up to race organisers, it is the umbrella organisation (in the UK, the BRCA) who set construction rules and checks suitability for a cell that has been sent for homologation. Then a race director has a definitive list from which to work from, exactly the same as Sub-C cells.

[joffacn]

In my Helis and Planes I only run Lipos and brushless and have just recently built my first buggy (D4).

The danger with lipos is incorrect charging (Cells Not Balanced), usage (used below 3V/cell) and storage (shorting out, either terminals or internal when cells are damaged).

There is a lot of info in the Aero forums (RCGroups,...)

I vote to keep the weight limit and voltage up to 7.4V nominal.

I am sure over time models will come out to take advantage of the weight distrbution options permitted by lipos.

The Li technology in the new round cells (ABC and others) coming out for power tools seem to be more robust but the V/cell (3.6) is lower than the Li poly gel cells (4.2). These cells are a different size to SubC.

Cheers Jeff

[mark christopher]

it has been said on here that if the weight limit was reduced car set ups would need to change, as cells have increased in weight from say 3300 to 4200's has the set up of cars changed to suit that?

[super__dan]

For me it's the voltage that's the biggest issue. Can they not be made to a nominal 7.2V?

[mark christopher]

nope its how thay are constructed, your seriously saying .2 volt is going to be a noticable advantage on the track?

the main thing is a lipo will hold its voltage over a 5 min run where mimh will drop off, but thats an advantage as it allows all to have good cells

[mark christopher]

DP delete please

[Chrislong]

nope its how thay are constructed, your seriously saying .2 volt is going to be a noticable advantage on the track?



Y E S

[tc2k]

But isnt a decent matched pack around 1.24v per cell, 6 x 1.24 is over 7.4v.

[mark christopher]

Y E S
so ur saying chris if i run lipo at 7.4 and you run nimh 7.2 im going to beat you all of a sudden? me thinks not!! u will still woop my ass prob even if u run 5 cell.

the other question, could you use the .2volt with the horse power we have in buggies what would you gain?

[DCM]

could with 4wd, if the cars were to be allowed to go lighter, softer tyres wouldn't rip up and you can, 2wd, no.

[mark christopher]

could with 4wd, if the cars were to be allowed to go lighter, softer tyres wouldn't rip up and you can, 2wd, no.
but myself and others are sayijng keep the same weights we have now!

[Chrislong]

so ur saying chris if i run lipo at 7.4 and you run nimh 7.2 im going to beat you all of a sudden? me thinks not!! u will still woop my ass prob even if u run 5 cell.

the other question, could you use the .2volt with the horse power we have in buggies what would you gain?

Stop trying to ram these bloody things down our throats! Go back to selling double glazing.

7.2v vs 7.4v is clearly different. Regardless of what magic the matchers work on them, the nominal voltages are different, there is a reason.

[vader]

http://trouble.philadelphiaweekly.com/archives/MERRY-GO-%20ROUND.jpg

[Chrislong]

Aye, it does feel like a roundabout... :D :D

[super__dan]

In off road I agree most of the time grip is out biggest limiting factor but battery voltage can still be hugely important. If only they could be 7.2V that would be fine with me. Whilst perhaps nimh have crept up past 7.2V nominal, what would then stop Lipo from creeping up past 7.4V nominal.

Unusually on the weekend because of the grass straight line speed (particularly in 2wd) was more important than normal. If I was maxed out for speed and someone was breezing past with Lipo I wouldn't be very happy.

Perhaps in my mind I can't get past how much quicker Jimmy's car was at the vintage with Lipo comparred to our 7.2v cells, the difference as I recal was very noticable.

The rest of the technology personally I'm OK with and recognise they form a large part of our racing future, just such a shame they don't compete on a completely level playing field.

[mole2k]

Personally I think Lipo will come but I cant see it being mainstream before 2010+

[mark christopher]

Stop trying to ram these bloody things down our throats! Go back to selling double glazing.

7.2v vs 7.4v is clearly different. Regardless of what magic the matchers work on them, the nominal voltages are different, there is a reason.
tut guess some peeps are still stuck in the 80's:mad:

[mark christopher]

Unusually on the weekend because of the grass straight line speed (particularly in 2wd) was more important than normal. If I was maxed out for speed and someone was breezing past with Lipo I wouldn't be very happy.

Perhaps in my mind I can't get past how much quicker Jimmy's car was at the vintage with Lipo comparred to our 7.2v cells, the difference as I recal was very noticable.



they could do that now if they were running a better motor or got the gearing spot on.

in a stock motor class they will have an advantage especially if there not run to the same weight limit

[DCM]

no, I disagree there Mark, the extra voltage allows you to run the same motor with taller gearing so it drives the same out of the corners, but where as you top out half way down the straight, they keep accelerating.

It isn't so much the nominal voltage, but how the power is produced too. The two couldn't sit very comfortably together, and in a competitive series, would mean everyone buying LiPo.

[mark christopher]

no, I disagree there Mark, the extra voltage allows you to run the same motor with taller gearing so it drives the same out of the corners, but where as you top out half way down the straight, they keep accelerating.

It isn't so much the nominal voltage, but how the power is produced too. The two couldn't sit very comfortably together, and in a competitive series, would mean everyone buying LiPo.
so you have seen then run side by side in a series?

i have and there is little differance and lipo did not wipe the floor, nimh was just as fast, and this was in 19 turn where voltage would help

[DCM]

with IB cells, and 19t, voltage is a killer not a saviour Mark....

[MattW]

Well, personally i'm very anti LiPo. Nothing to do with the voltage. At the moment, there is little or no development in the LiPo RC market (at least not the development that we can all see in the NiMh market). However, i've spoke to a few poeple in the know and they assure me that if the development was required (i.e they were actually used for racing) then that development would be at a pace that we have never seen before. I said this before - and i believe Mark C started that thread as well.

What i will say though, is that i have run LiPo back to back with IB NiMh cells, and i have to say i didn't notice a difference. In fact, if i'm really being honest, i think new ish Ib's are probably faster. This is a point that was confiremd by a friend of mine at my locak club last week. He's been running LiPo for ages, but bought a couple of packs of NiMh as he needed them for a BRCA meeting.

[modelimages]

ok and a higher voltage (all be it .2volt) does what to amps for the same wattage draw?
at biws in 6 cell touring car lipo and nimh ran side by side lipo took one win, (all cars to same weight) the advantage is in no loss of performance and easier charging.

if miss used they do go bang yes, but so does any form of power cell. to date only nimh has cost one racer a very badly injured eye and another not so good, lipo has non documanted. simply dont miss use em (corectly charge and dont go below 6 volts) and there safe, how many carry em in your pocket? (mobile phone)
to say they go bang and plead ignorance to any other cell being a danger is very poor knowledge!

i have an opinion, i gave it, i don't really need the personel insults, at no point did i plead ignorance to any other cell going bang, i am pointing out that these cells require a little care when in use and when charging and that that is different to the current cells.

voltage differences, yes you can buy nimh packs with nominal voltages of each cell being higher than 1.2v, thats why people spend hours looking through new cells to find those elusive high voltage ones, its why matching companies exist. i just checked the figures on a 6 pack of ib4200 the total for all 6 is 7.41v, thats a top spec and top price matched pack and it equals any 2cell lipo, you would assume therefore that a top spec top price lipo will of course be higher than 7.4. i cannot see how two batteries with different nominal voltages could race together without one racer believing he was at a disadvantage. if your saying that there is no performance difference between these packs then that begs the question why would you fit one, i don't need anymore duration, i would need a different charger and they cost more. not exactly appealing at the moment. so what advantages would buying this type of battery give me?

[mark christopher]

i have an opinion, i gave it, i don't really need the personel insults, at no point did i plead ignorance to any other cell going bang, i am pointing out that these cells require a little care when in use and when charging and that that is different to the current cells.

voltage differences, yes you can buy nimh packs with nominal voltages of each cell being higher than 1.2v, thats why people spend hours looking through new cells to find those elusive high voltage ones, its why matching companies exist. i just checked the figures on a 6 pack of ib4200 the total for all 6 is 7.41v, thats a top spec and top price matched pack and it equals any 2cell lipo, you would assume therefore that a top spec top price lipo will of course be higher than 7.4. i cannot see how two batteries with different nominal voltages could race together without one racer believing he was at a disadvantage. if your saying that there is no performance difference between these packs then that begs the question why would you fit one, i don't need anymore duration, i would need a different charger and they cost more. not exactly appealing at the moment. so what advantages would buying this type of battery give me?
it was not meant as a personal insult, but any cell is danjerous and in no way are lipo anymore danjerous as a normal nicad/nimh in use or charge,
its been said on here by many and i will say it again, if you run them in the correct way they are not danjerous, if i abuse nimh they can be danjerous.

they are dearer pack for pack yes BUT two packs will see you for a weekend racing, with no loss in performance
most chargers can do lipo and a good one can be had for £50 which i have posted in this thread along with the other advantages!
weight = can be placed where you want it if you need to run to current weights
need less packs
no need to discharge equalize
no perormance loss over thier life span
can be charged weeks before and dont loose power, fit and go

what does amaze me though is the amount of posters who know all about them but have not actually used them:o

i have both lipo set up and good nimh so either way im not bothered where it goes, though i do enjoy the lipo ease of use.
i just wanted to see 6 months on how lipo was percieved. more clubs are allowing them and definatly more manufactures (rc ones) are producing/selling them. as i see it many do regionals and not nationals and to me (note to me) they should be allowed at club and possibly regionals.
my stipulation would be only lipo in a hard case, and if using lipo proof should be shown your charger is lipo compatable and poss even a 6 volt cut of is used weather an external or a speedo device (though if you have half a brain the last one is not needed)
i have found that off road electric to be the freindlyist class i have raced this year, with the least amount of rules (only sensible fair ones used) the cheapest by far and dam good fun.
lipo would make it better for me personally but in no way is off road broke or full of borats nieghbours!!

[DCM]

what does amaze me though is the amount of posters who know all about them but have not actually used them:o

It's called research and reading manufacturers technical specification that gives you a grounding on how a particular item works, it isn't rocket science.

You forget to say that most NEW chargers are lipo enabled. I have two chargers here that are not, and four that are.

I will come back to my original concern with the cells, is that, unlike all other cells previously, they could all be charged with older chargers, LiPo can't and needs a specifically LiPo programmed charger, plus, running them below voltage causes issue's too. This is where the crux of the problem is, for me. Where as the educated racer will know what to do, the majority of bashers and club level racers wont. There is no backward compatibility in them.

[Cockerill]

what does amaze me though is the amount of posters who know all about them but have not actually used them:o

Thats because most racers on here race at BRCA sanctioned events, therefore cannot justify buying LIPO packs that cannot be used. However, we can still read up about them.

[mark christopher]

Thats because most racers on here race at BRCA sanctioned events, therefore cannot justify buying LIPO packs that cannot be used. However, we can still read up about them.
is that why club numbers are down? thay all do nationals and no club racing?
how many national racers chargers are lipo ready?

[DCM]

Mark, this has a veil of you trying to provoke discussion/argument.

Lots of clubs run to BRCA rules, so LiPo ain't allowed, period, till they are allowed and then it will be at the clubs discretion.

No matter how much you 'Big Up' LiPo, till people are comfortable with a totally new power source...... you are wasting bandwidth.

[neiloliver]

The nominal voltage of Nickel coupled cells (NiCd and NiMH) is based on the electrochemical couple which is around 1.20V. The actually running voltage depends on the load mostly but the age of the cell also reduces running voltage. Cell manufacturers can also add additives to both the electrodes and electrolyete to increase voltage, usually at the expense of another performance attribute (this is one of the reasons why IB4200 cells have such high voltage but they dont last very long in terms of cycles).

For Lithium ion and lithium polymer cells, the voltage is based on the average voltage when the cell is discharged at the 5 hour rate and this is typically 3.6V or 3.7V (Some of the cylindrical 18650 cells developed for power tools are now 3.8V) at this 5 hour rate.

Personally, i think lithium polymer is the wrong cell technology for RC cars, the 18650 (18.0mm diameter and 65mm height cell) which has been used in notebooks for the past 10+ years is now finally making it's way into powertool although the cells are only around 1.5Ah in capacity due to their need to deliver high currents.

A 2S2P 18650 battery pack would be ~7.4V 3000mAh and could be manufactured in either stick or saddle pack, have built in electronics for over voltage protection and over discharge protection (like a power tool battery). The current situation in which cells rely on the user to protect them is not a good one. It would not be entertained in the "real" world of consumer electronics and OEM electronic products. I wont let a lithium ion battery leave our factory without adequate protection and customer who want unprotected cells are told to buy them from someone else...

There are great LiIon possibilities for RC cars but i think the technology should be adopted from the powertool market in the same way as NiCd and NiCd was (because if it was not for powertool, the Cs cell would not exist).

The last bit of my rant is about transport. Did you know that transporting Lithium ion cells or batteries is being controlled more and more, they have to undergo many safety tests before they can be transported on aircraft. Any modification to these cells or batteries woudl mean a re-test. Anyone who buys cells and makes their own battery and then takes them on an aircraft woudl be breaking international law. Pre-tested, assembled battery packs are the only way this can go in the future.

N

[Chrislong]

Hi Mark, email Charlie Fraser who is the secretary for the BRCA with the proposal of Lipo at regional level for the AGM. Next, make sure you go and attend the AGM later this year and be the one to vote it, it may get seconded and approved or there may be valid reason that it can't be - if so, they'll be explained... either way, will you be content?

Spoiling of a thread with many arguements isn't healthy, and surely the above should be done before it really is worth continueing with any discussion.

From my point of view, I will not consider buying Lipo until it is allowed at nationals, and proven to me that it is better (purely performance wise) than Nimphs.

[mark christopher]

it was not meant as a personal insult, but any cell is danjerous and in no way are lipo anymore danjerous as a normal nicad/nimh in use or charge,
its been said on here by many and i will say it again, if you run them in the correct way they are not danjerous, if i abuse nimh they can be danjerous.

they are dearer pack for pack yes BUT two packs will see you for a weekend racing, with no loss in performance
most chargers can do lipo and a good one can be had for £50 which i have posted in this thread along with the other advantages!
weight = can be placed where you want it if you need to run to current weights
need less packs
no need to discharge equalize
no perormance loss over thier life span
can be charged weeks before and dont loose power, fit and go

what does amaze me though is the amount of posters who know all about them but have not actually used them:o

i have both lipo set up and good nimh so either way im not bothered where it goes, though i do enjoy the lipo ease of use.
i just wanted to see 6 months on how lipo was percieved. more clubs are allowing them and definatly more manufactures (rc ones) are producing/selling them. as i see it many do regionals and not nationals and to me (note to me) they should be allowed at club and possibly regionals.
my stipulation would be only lipo in a hard case, and if using lipo proof should be shown your charger is lipo compatable and poss even a 6 volt cut of is used weather an external or a speedo device (though if you have half a brain the last one is not needed)
i have found that off road electric to be the freindlyist class i have raced this year, with the least amount of rules (only sensible fair ones used) the cheapest by far and dam good fun.
lipo would make it better for me personally but in no way is off road broke or full of borats nieghbours!!

Hi Mark, email Charlie Fraser who is the secretary for the BRCA with the proposal of Lipo at regional level for the AGM. Next, make sure you go and attend the AGM later this year and be the one to vote it, it may get seconded and approved or there may be valid reason that it can't be - if so, they'll be explained... either way, will you be content?

Spoiling of a thread with many arguements isn't healthy, and surely the above should be done before it really is worth continueing with any discussion.

From my point of view, I will not consider buying Lipo until it is allowed at nationals, and proven to me that it is better (purely performance wise) than Nimphs.
Chris
your red questions is answered in my previous post (in red)
there is no point in proposing it if the majority of racers on here dont want it (most on here would be at the agm),if its not wanted by the majority i have no intention of trying to force/push lipo in.
as i have put off road aint broke and i have all the eqiupment i need to run either cell format!
as i have put before i was interested in what had changed with drivers views now they are more "out there"
it seems to me those who have them like em, those who dont are either not sure or go on what they read resulting in some for and some against.


DCM i have asked for it to be discussed is that not what a forum is for?

[Lee]

Im no lipo fan either, i have run them in the TC a while ago and at the time they did give a slight performance increase, but this only helped to throw a wind quicker so therefore rendered them useless.

In off road we dont need more runtime, we dont need more "power" and frankly if i wasnt charging cells between runs i would have nothing to do once i go brushless.

[mole2k]

My local club runs 19t buggys indoors on polished wood, I would quite like to see Lipo purely from a maintenance factor. It would leave me free to do more work on the car or help some of the other members.

I do agree with Neil Oliver that I think the packs should come pre-assembled perhaps with just the option of a splitting a stick pack and have discharge protection circuitry built into the battery itself. You very well may argue that this is unessecary as some speedo's have it but the fact still remains a lot of speedo's do not have the lipo protection.

[PaulRotheram]

i cant see where people are coming from with having more spare time by running lipos.. how long does it take to press the bloody start button with nimhs?

[mole2k]

Its not just time at the meeting, its time beforehand too. When racing weekly meetings and trying to charge batterys during the day.

[Spencer Mulcahy]

I dont think I will be going Lipo as I dont think it is needed in cars helicopters or planes maybe. As for being stuck in the 80s that is defo me as I have decided to ditch brushless and go back to brushed. Brushless to powerfull for me and my driving has gone backward.

[Richard Lowe]

I see no reason not to move to Lipo's once they are 100% idiot-proof, I'm looking forward to using them purely because of the lighter weight. Quicker acceleration/direction change, less wear on things; including tires, whats not to like? They will make the cars handle differently but thats nothing a change in setup won't fix, less pack and softer springs would be all thats needed. Adding weight to a car to make it handle properly is wrong if you ask me, if you're at the weight limit and you are having to add weight to the car either your setup or the cars design isn't right.

The extra voltage is a bit of a problem and would mean it wouldn't really be fair to run Lipo's and NIMH's togeather. Though there's nothing stopping us making the cars a bit of a handful to drive with NIMH's and brushless currently, especially in 2wd.

[MarkWesterfield]

One battery making an r/c car faster over another battery isn't really an issue. Nimh have this problem now, IB4200's are faster than the old gp3300, and everybody has IB4200's in their pits, so nothing will change with the 7.4 lipo batteries. The fast drivers will still be fast, the slow drivers will still be slow. One big problem I see is that its very easy to permenantly damage a more expensive lipo pack by running it under 3 volts per cell. Lipo cutoff speed controls are not enough of a standard yet.

I think keeping the minimum weight the same, and setting a future date far enough ahead for lipo legalization so everybody has plenty of opportunity to learn, buy, and adapt to lipo is the way to go. Say if the date was July 1st, 2008 for 7.4 volt 6000mah capacity lipo to be legal, I think the switch would go over smooth. Thats a year to buy a charger, batteries, and lipo freindly speedo's. I think a timeframe to a standard is what is needed.

[MarkWesterfield]

Richard,

Softer springs and less pack will not fix the amount of weight loss. The contact patch of the tire is smaller with less weight. You'll need softer compound tires and inserts to regain the traction as well, softer compound tires will wear faster (the car is still going the same speed), so you'll be right back in the same spot as far as tire wear.

[Richard Lowe]

Softer springs and less pack will not fix the amount of weight loss. The contact patch of the tire is smaller with less weight. You'll need softer compound tires and inserts to regain the traction as well,
Remember you have less weight to move around... ;)

[MarkWesterfield]

but that weight is needed for the current tire designs to work correctly.

[Northy]

but that weight is needed for the current tire designs to work correctly.

Er.... certainly in the UK tyre design has not changed as cars have got heavier, and it would be the same for everyone anyway.

G

[mark christopher]

just to point out im answering questions not looking to arguee............chris/dcm!!:)
i cant see where people are coming from with having more spare time by running lipos.. how long does it take to press the bloody start button with nimhs?

there is no discharging/equalizing/charge from flat, time is saved by finish your run, marshal (allow pack to cool) plug in charger and top up, so you can turn car round far quicker.
im lucky and have 4x lipo (which i loan 2 out for trial to anyone.) but in theory i could turn up with 4 packs and run a days racing without taking a charger and have the same performance, dont think i could with pre charged nimh charged the week before.


My local club runs 19t buggys indoors on polished wood, I would quite like to see Lipo purely from a maintenance factor. It would leave me free to do more work on the car or help some of the other members.

I do agree with Neil Oliver that I think the packs should come pre-assembled perhaps with just the option of a splitting a stick pack and have discharge protection circuitry built into the battery itself. You very well may argue that this is unessecary as some speedo's have it but the fact still remains a lot of speedo's do not have the lipo protection.

you can buy seperate voltage cut offs, novak, trakpower,jperkins and others all do em. when 6 volts is reached they cut the radio, i have used trakpowers and for a few seconds it stutters the motor then shuts the speedo down via the reciever link, they are relativly cheap, small and light

[mark christopher]

Im no lipo fan either, i have run them in the TC a while ago and at the time they did give a slight performance increase, but this only helped to throw a wind quicker so therefore rendered them useless.

In off road we dont need more runtime, we dont need more "power" and frankly if i wasnt charging cells between runs i would have nothing to do once i go brushless.


howe about chatting with some mates?;)

[DCM]

you can buy seperate voltage cut offs, novak, trakpower,jperkins and others all do em. when 6 volts is reached they cut the radio, i have used trakpowers and for a few seconds it stutters the motor then shuts the speedo down via the reciever link, they are relativly cheap, small and light

For me, that needs to be built into the pack not an add-on extra, as the low voltage can cause dire affects on the cell, so for a safety stand point, that needs to be fool proof, plus hard casing, then I think they would be viable as a cell, but until then, there is still a lot of reliance on peoples common sense.

[Cockerill]

To say that we won't have to equalise lipo's is just stupid. There are two cells in a pack and there are already equalisers on the market. Ensuring both cells are the same will be a performance advantage.

Richard,

Softer springs and less pack will not fix the amount of weight loss. The contact patch of the tire is smaller with less weight. You'll need softer compound tires and inserts to regain the traction as well, softer compound tires will wear faster (the car is still going the same speed), so you'll be right back in the same spot as far as tire wear.

I'm sorry, but if you are running the same tires surely you have the same contact patch, but less pressure. However, as there is less weight to move around you don't need as much pressure.

As batteries have got heavier I have not seen a harder compound released.

[PTRU]

FYI

At regional level you can amend the rules to suit under serton sections this being one if you take time to read the rules.

We allowed brushless to run 2 years before they became BRCA legal in our region so people could run with them if they turned up. I for 1 would not stop these battery's being used in the region as long as they do not give a health problem.

The reason for falling numbers at club level is many fold one being and the main one is there is not enough juniors U13/U16 coming into the sport this is the biggest fall in numbers, Dads have other things they wish to do with there time.

If you put a proposal into the BRCA it will be discussed at the AGM, you as a proposer will be able to put your piont of veiw across, how well you sell it is down to you. It will also be discussed at commite before hand.

I know this has been mention before but you will get a fare chance for your proposal.

If you do what most people do:- Nothing then carry on and moaning.

[mark christopher]

To say that we won't have to equalise lipo's is just stupid. There are two cells in a pack and there are already equalisers on the market. Ensuring both cells are the same will be a performance advantage.


not so
trakpower have a pack thats done over 100 cycles in a car and its still no diferent,

however you do not have to equalize lipo prior to charging you balance lipo and it will become the norm as good lipo chargers have it built in and the add ons balance the pack but its done whilst charging so it does not alter the cool/charge time

[mark christopher]

FYI

At regional level you can amend the rules to suit under serton sections this being one if you take time to read the rules.

We allowed brushless to run 2 years before they became BRCA legal in our region so people could run with them if they turned up. I for 1 would not stop these battery's being used in the region as long as they do not give a health problem.

The reason for falling numbers at club level is many fold one being and the main one is there is not enough juniors U13/U16 coming into the sport this is the biggest fall in numbers, Dads have other things they wish to do with there time.

If you put a proposal into the BRCA it will be discussed at the AGM, you as a proposer will be able to put your piont of veiw across, how well you sell it is down to you. It will also be discussed at commite before hand.

I know this has been mention before but you will get a fare chance for your proposal.

If you do what most people do:- Nothing then carry on and moaning.
what region are you in?

[PTRU]

Chilton mid south

[mark christopher]

For me, that needs to be built into the pack not an add-on extra, as the low voltage can cause dire affects on the cell, so for a safety stand point, that needs to be fool proof, plus hard casing, then I think they would be viable as a cell, but until then, there is still a lot of reliance on peoples common sense.
i agree with most of above but to me adding the cut off to the pack is not a forward move,
1/ it will increase the cost of each pack
2/ your forcing drivers who have a lipo speedo to buy an additional cut off
3/ to remove pack you now need to also remove the reciever wiring from the pack
4/ its easy ot check a lipo speedo or a voltage cut off is fitted.

5/ all systems can be by passed so your back to common sence.

i have purpesly run a trakpower pack till flat, on my own in an open empty space as i like to experience what i preach where possible, no explosion, no fire, the biggest problem is in fact shorting the cell, which is a hazard to any cell format.
we have to educate and trust racers to act sensibly, thay already have that trust.

[mark christopher]

Chilton mid south
typical, wrong end of country, dont get me wrong if it was aimed at me, im not moaning, im happy to use either cell format.

[DCM]

I think it was Neil who said it before, but you won't buy a consumer peice of equipment that was built that didn't protect you and itself from a harmful discharge.

If the system is built in, then it can be used on ANY esc without issue. If them someone is stupid enough to bypass it, then that is there problem, but for the rest of us, it is peace of mind. If you want them more widely used then they HAVE to be user friendly out of the box, not needing this and that to plug in to make them safe for use (and I mean protected from under voltage situations...)

If I was the BRCA, then that is what I would insist as a primary part of the construction rules of the cell. I mean, if we wanted them cheap, we could just keep with the foil gel sacks and a fancy sticker, but that would not puch the cells along the way of acceptance would it.

[Cockerill]

Balancing/Equalising are pretty much the same thing. Altho it may not take extra time it is still an extra piece of equipment to purchase or a feature to pay for, and you are trying to say that it will not be necessary. Whilst it may not, the likely hood is that if there is an advantage to be gained by doing it, racers will.

We don't necessarily need to equalise nimh's, but the majority do because there is an advantage to be had.

[mole2k]

you can buy seperate voltage cut offs, novak, trakpower,jperkins and others all do em. when 6 volts is reached they cut the radio, i have used trakpowers and for a few seconds it stutters the motor then shuts the speedo down via the reciever link, they are relativly cheap, small and light


I actually have a lipo cut off in my speedo but I still think from a safety point of view it should be included in the packs themselves, not for racers but for bashers and juniors who tend to run cars out in carparks untill the batterys run flat.

[Chris Doughty]

if you want 'safe' (along the lines of hard case etc...) why not go the whole hog and have min-discharge and max-charge cut-off's for the pack.

if you want cheep, just go shrink wrap and solder tabs.

it would be great if manufacturers had some proposed construction rules for LiPo cells, that might help LiPO evolve and become mainstream?

[DCM]

I agree Chris, at the moment, they are going their merry own route, what will happen, is one will become popular and construction rules will stem from them and everyone plays catch-up.

[mark christopher]

I actually have a lipo cut off in my speedo but I still think from a safety point of view it should be included in the packs themselves, not for racers but for bashers and juniors who tend to run cars out in carparks untill the batterys run flat.
in theory yes, but you would need some heavy elrctronics to do it as a cutr off in the pack and it will have to be able to carry the max current of the pack, as the only way it can stop the pack going flat is cut the main output cables.
this would then reguire a curent to operate which would still draw power when the cell was below 6 volt or it would not come back to life

[MarkWesterfield]

I'm sorry, but if you are running the same tires surely you have the same contact patch, but less pressure. However, as there is less weight to move around you don't need as much pressure.

As batteries have got heavier I have not seen a harder compound released.

If the tires were solid with no flex, then there would be no change in contact patch, just pressure as you said. But tires are made of flexible rubber compounds that flex and conform to the track surface, especially during weight transfer while corning, braking or accelerating. less battery weight = less contact patch and less weight to transfer (for an increase in contact patch) = less traction. Ask a tire manufacturer. You will still need just as much pressure for the same given tire for the same given traction conditions to go through a corner at the same speeds. You will end up needing softer tires, trust me, thats why everybody adds the weight back to their car with lead. Another bit of physics...by reducing the weight of the heaviest part of an r/c (the battery) that is located in the lowest part of the car, you effectivly raise the center of gravity of the car. Thats why is not just less damping and softer springs to make the cars handle right. Alot of things change when you reduce the weight of our little precision toys by 200 grams.

The minimum weights allowed for the cars haven't changed, so over the years as the batteries got heavier, the car designers designed lighter chassis to bring the cars to minimum legal weight...tires did not need to be harder because the net weight of the car and batteries were still the same.

[Chris Doughty]

but you are also reducing the amount of weight the tire has to 'hold' in the turn.

running the same set of tires I would favour a super light car at pulling lateral G's versus a big fat mama of a car. (even if running hard tires)

[Chris Doughty]

one thing I have noticed with regard to LiPo Vs Nimh...

the EB legalise the use of a 'cell' we then make them up as our own packs of batteries etc...

but it seems with LiPo, people have completely forgot about the 'cell' and are just bothered about the 'pack'

with no 'rules' or legality for the 'cell' part of a LiPo pack it could mean a big can of worms? as long as the 'pack' is LiPo and 7.4v is it 'OK'?

this seems to be a(nother) big differance between LiPo and Nimh mentality

I just through I would throw in this curve ball, I have not seen this element of 'LiPo vs Nimh' debate yet so off you go... :rolleyes: :o :p

[mark christopher]

hmmm good point chris, i supose it would be fair to say you carnt publicly buy a loose lipo cell to make a pack maybe it needs to be a pack dimension? must be only so much you can get into a box

[Chris Doughty]

I was thinking more along the line of, you buy IB cell's in a 'pack' via LRP (as VTEC) or Orion/Peak etc... you don't normally buy them from IB.

now I know LiPo packs SHOULD come pre-assembled but I believe it would benefit us all if they were made (by the RC company) from a certain 'type' of LiPo cell. for example a 2500mah 3.7v ***x*** size cell. they would proberbly end up in a 2s2p format inside the 'pack' in the same way that our IB cells end up in a 6s1p format.

in the same way that LRP or Orion buy in from IB and they make up their packs from this.

that way there could be a lipo battery list for the 'cell' type and homologated 'packs' are tested and proven to be made up of these cell types.

it just bring about a more 'standardized' LiPo field. I think thats why people like nimh's, we pretty much 'know' what we are getting. LiPo is so 'new' that you get some many crazy combos of batteries.

[mark christopher]

how do you mean crazy combo's?

[Chris Doughty]

some batteries at 4900mah, 3.7v in 2s1p
some 2500mah 3.7v in 2s2p
possible combo of 1000mah in 2s4p etc...

right now for nimh we pretty much have 6s1p and thats it, only the cell 'technology' which is only approved once a year changes to give us more capacity or voltage.

you don't see us finding some 2500 duracel AA's and using 12 cells to make a 6s2p 5000mah 7.2v pack

[mark christopher]

some batteries at 4900mah, 3.7v in 2s1p
some 2500mah 3.7v in 2s2p
possible combo of 1000mah in 2s4p etc...

right now for nimh we pretty much have 6s1p and thats it, only the cell 'technology' which is only approved once a year changes to give us more capacity or voltage.

you don't see us finding some 2500 duracel AA's and using 12 cells to make a 6s2p 5000mah 7.2v pack
are they sold as car packs? got to admit only looked at the main manufacures

[Chris Doughty]

if you talking about the 'duracel' thing I just made that up as an example of how we 'could' make a 7.2v nimh 'pack' of cells but the 'rules' that we have (homologated cells of a certain type (subC) mean that it rules out this combo.

[mark christopher]

meant the combo of lipo

think it needs to be 2 cell in series but then a saddle pack would need to be 2x 2 cell so four cells in total

[Chris Doughty]

obviously 2 cells in series to get the voltage.

but the LRP pack has 2x 2500mah cells in parallel too (2s2p)

it is theoretically possible to get 10 500mah lipo cells in paralell and then 2 of those 'sets' in series do make a 2s10p 5000mah 7.4v lipo pack.

see what I mean, the combo's are almost endless.

I like the fact that nimh have a nominated cell 'size' (SubC)

nothing like this exists for LiPo. from what I understand Kokam seem to be like an IB equiv for LiPo, I am pretty sure Orion/Peak use Kokam for their cells.

is there a 'size' chart for LiPo like there is for nimh (AA, C, SubC, AAA and so on)

[mark christopher]

no idea chris about size chart.

[neiloliver]

if you want to see charts, then look at
http://www.kokam.com/english/product/battery_main.html

Kokam make the cells for the Orion packs. i have not examined the list in detail to see which cell they use, but as you can see, the range is wide. Polymer cell tooling is far more flexible than for cylinrical cells so the cost for tooling a special size is thousands of dollars rather than hundreds of thousands. I suspect Kokam use two cells or maybe four in the orion packs, depending how thick they can go with their lamination process. Jimmy and I did discuss me taking one of his packs apart for testing but we never got around to it!

I set x/y/z dimension for the cells would be a good start when talking about setting a standard.

Neil

[Chris Doughty]

would anyone know how (from waaaaay back in the day) we decided that using SubC size ni-cad and nimh cells was going to be the 'standard' for electric racing?

not just 'how' but maybe 'why' we choose this size too?

[neiloliver]

Cs is the industry standard for cordless powertool (23dia43 height) and powertools were to only products with cells capable of delivering high enough currents. NiCd cells started at around 1300mAh (When I started at Ever Ready in 1989 we were still making 1300mAh NiCd cells!) and then steadily progressed to 1900mAh, then to 2400mAh. NiMH for powertool started at 2.0Ah in 1997 (our company lauched the first cell with Makita in that year) and are now between 2600mAh and 4200mAh.

Cs is very versatile when making packs because its diameter is 2x its height.. this makes is tessolate very well in packs when you want to make them into cluster packs for drills, saws etc..

This is why RC cars use Cs.. because of Cordless Powertool. The RC car market is an itsy bitsy % on the end of a pin compared with powertool globally..

Personally, i think it went pear shaped around three years ago... when the Chinese started to enter the market. you see up until then, we used the best of the powertool cells (N-1900SCR, N-2400SCR) from the likes of Sanyo and Panasonic. Being japanese the performance was good and the reliability was also good. The chinese have up'd the capacity and voltage but at the expense of reliability.. the japanese are not following the chinese into this niche market because it does not play to their global goals... but it does mean that to be competititve we have to use hand built chinese cells that dont last so long..

dont get me onto batteries.. i have had enough of them now!!! :(

[mark christopher]

if you want to see charts, then look at
http://www.kokam.com/english/product/battery_main.html

Kokam make the cells for the Orion packs. i have not examined the list in detail to see which cell they use, but as you can see, the range is wide. Polymer cell tooling is far more flexible than for cylinrical cells so the cost for tooling a special size is thousands of dollars rather than hundreds of thousands. I suspect Kokam use two cells or maybe four in the orion packs, depending how thick they can go with their lamination process. Jimmy and I did discuss me taking one of his packs apart for testing but we never got around to it!

I set x/y/z dimension for the cells would be a good start when talking about setting a standard.

Neil
track power are defo two cells as they let me take one apart, orion are too as they only have one balance conector and the two main outputs

[Chris Doughty]

Neil, good background info....

so the reason RC started to use subC was becuase that was really the only thing that could deliever the output we wanted...

for LiPo, it seems most of them can do that, how what or why would be used to 'choose' a LiPo 'cell' size/type?

maybe this is not such a stable idea, like was said before, if tooling for cell sizes are relatively cheep for LiPo then we are not as restricted to a certain size.

[neiloliver]

If the cells are in parallel they balance themselves anyway. You only balance cells in series with each other. Computer batteries (well at least the ones we design) have the balancing built into the battery and it is done automatically during charge (a voltage detection IC senses the higher voltage cell in the string and bypasses its charge current through a resistor, effectivly allowing the other cells to 'catch up'. The balancing via discharge is the second way of balancing but is a bit crude.

I would love to get one of these packs to test, i might need to do that soon in the name of competitive product research ;)

[mark christopher]

Neil which pack to test?

[mark christopher]

Neil, good background info....

so the reason RC started to use subC was becuase that was really the only thing that could deliever the output we wanted...

for LiPo, it seems most of them can do that, how what or why would be used to 'choose' a LiPo 'cell' size/type?

maybe this is not such a stable idea, like was said before, if tooling for cell sizes are relatively cheep for LiPo then we are not as restricted to a certain size.
thats the bueaty of lipo chris im in the process of doing recievers pack of various sizes, because it can be done.
i also run em in my handset. KO helios, and they last for ages and run at 12 volt! ( 3 cell of course)

[neiloliver]

Neil which pack to test?

The most popular one i guess.. The orion Kokam one woudl be a good start because Kokam are a 'proper' company.. I dont know who in Asia makes the cells for the other models out there..

Mark.. can you give me a summary of the main few 7.4V packs that come with proper hard plastic cases?

[mark christopher]

orion do two as i presume do peak, not sure if lrp are hard case (chris can you help)?
trakpower http://www.flighttech.co.uk/
to be honest im not sure other than them who does what as i consider these to be the top sellers

[neiloliver]

i did some browsing last night and I think the Trackpower (gold thing that Jimmy reviewed) with cells made by 'Enerland' and the Orion (with cells made by 'Kokam') seem to be the two most popular. I have not seen any hard cased saddle pack models though, just soft packed ones.

N

[mark christopher]

i did some browsing last night and I think the Trackpower (gold thing that Jimmy reviewed) with cells made by 'Enerland' and the Orion (with cells made by 'Kokam') seem to be the two most popular. I have not seen any hard cased saddle pack models though, just soft packed ones.

N
track power are working on some,
my thoughts is hard case is a must reguirment

[Chris Doughty]

LRP is just 'heavy' shrink wrap with 'heavier' end peices

its semi-transparant so you can see the 4 lipo cells (they are 4 stacked on top of each other)

[neiloliver]

Full injection molded cases are the way to go. Lithium polymers cells are very suceptable to mechanical abuse, even running your fingernail over the metal foil can create an abnormal resistive path within the cell which can degrade it's performance. The case would not help you if all hell broke loose within the cell, but it will help protect it if your saddle packs trail out of the side of your car like zombie entrails following a shunt!